Telephone.



No. 64|,570. v Patented lan. I6, |900.

- D. H. WILSON.

TELEPHUNE.

(Application fixed Jan. 2o, 1399.)

(No Model.)

wur

Elzas C0. woaumo., wummoroN D c (Application led Jan. 20, 1899-) I 2Sheets-Sheet 2.

(No Model.)

w .mwN

HMI

NTTED STATES DAVID H. wILsoN,

PATENT FFICE..

TELEPHONE.

SPECIFICATION forming partof Letters Patent No. 641,570, dated January16, 1900.

Application filed January 20,1899. Serial No. 702.777.y (No model.) g

T0 @ZZ whom t may concern:

Beit known that I, DAVID H. WILSON, a

citizen of the United States, residing at Chicago, inthe county of Cookand State of Illinois, have invented a certain new and usefulImprovement in Telephones, of which the following is a speciiication.

My invention relates to telephones, and has for its object to provide anew and improved telephone, of which the following is a description,reference being had to the accolnpanying drawings, whereinv Figure l isa diagrammatic view showing a device embodying my invention. Fig. 2 is adiagrammatic view showing a modified construction. Fig. 3 is a sectionon line 3 3, Fig. 2. Fig. 4 is a plan view of the core and primary andsecondary coils shown in Fig. 3.

Like letters refer to like parts throughout the several figures.

Referring now to Fig. l, I have shown diagrammatically a constructionembodying my invention, the drawing showing only two i'nstruments A andB for purposes of illustration. In this construction each instrument isprovided with a suitable transformer of any description, comprising aprimary coil O and a secondary coil D'. One terminal of the primary coilis connected with the transmitter C', the transmitter being connected byconductor O2 with a source of electric supply Cs at station A. The otherterminal of the primary coil is connected by conductor O4 with asuitable circuit-varying device, by means of which it is connected withthe main line E. As herein illustrated, I have shown the circuit-varyingdevice as consisting of an ordinary hook O5, upon which the receiver issuspended. The conductor O4 is connected with the contact O5, opposed tothe contact O7., associated with the hook O5. The secondary coil D isconnected by conductor Dl with a suitable circuit-varying device, whichin this case consists of the contact D2, opposed to the contact DS onthe receiver-hook O5. The contact D5 is connected by conductor D4 withthe" receiver D5, said receiver being connected by conductor D6 with theother terminal of the secondary coil. When an ordinary transformer isused, a suitable signaling device must be provided. Anysuitableconstruction for this purpose may be used. As

line E. When it is desired to signal instrun ment B, for example, thesource of electric supply is rendered operative, and a current is passedthrough the system, which is traced as follows: from the source ofelectric supply through conductor F5, contacts F4 and F5 and conductor Ftothe main line E, and thence through the signaling device of theinstrument B, so as to actuate it. The current then passes to theground, so as to complete the circuit. After the signal has been sentthe re'- ceiver is removed from the hook O5. The hook O5 then moves soas to separate the contacts F4 and F5 and complete the circuit betweenthe contacts C5 and C7 D2 and D5. The talking-circuit will then becompleted and will be as follows: from the source of electric supply C2through conductor O2 to transmit ter C', thence through the primary coilC, thence through conductor C4 and contacts C6 and C7 to the main lineE, thence through the primary coil of the instrument B, thence to theground and back to the source of electric supply O3. The current in theprimary coil sets up an induced current in the secondary coil D of theinstrument B, which passes through the receiver, the circuit beingtraced as follows: from the secondary c oil D through conductor D5,receiver D5, conductor D4, contacts D3' and D2, and conductor D back tothe secondary coil D. It will be seen that the primary circuit in thiscase constitutes the main line ofthe system and that the source ofelectric supply and the transmitter are directly in this mainline. seenthat the receiver is not in the main line,

but is in a local secondary circuit at the re-v ceiving instrument.

Referring now to Fig. 2, I have, shown diagrammaticallya constructionsimilar to that shown in Fig. 1, wherein the induction-coil It will alsobeis of a peculiar construction. Said inductioncoil consists of a coreG, upon which are wound the primary and secondary coils C and D, saidcore being mounted between the opposed pole-pieces of a permanentmagnet. By rotatably mounting the core G and the primary and secondarycoils and providing suitable commutatore G G2 and a crank or handle G3for the shaft I may do away with the extra signaling devices and use thetransformer for this purpose. I find that when this particulartransformer is used with the arrangement herein shown better results areproduced than when the ordinary transformer is used. YVhen the parts arearranged as shown in Fig. 2 and it is desired to call up instrument B,the core G is rotated by means vof the handle G3 and a series ofimpulses sent out upon the line. The circuit will be traced as follows:from the secondary coil D by conductor DG to contact F4, thence throughthe receiver-hook C5 to the main line E, thence through the secondarycoil of instrument B andthe signaling device F to the ground, and thencethrough the signaling device of instrument A back to the secondary coil.If the receivers are now taken from the hooks, the talking-circuit iscompleted and will be as follows: from the source of electric supply C3through the transmitter C', contacts C and C7, and primary coil C to themain line E, thence through the primary coil of the instrument B, andthence through C7 CG and the transmitter to the ground, the circuitbeing provided with a ground return. A current is then generated in thelocal secondary circuit containing the receiver of instrument B, saidcircuit being traced as follows: from the secondary coil of thetransformer through conductor D6 to the receiver, thence by conductorD4, contacts D3 and D2, and conductor D' back to the secondary coil.

IVhen the construction herein shown is used, I find that highlysatisfactor f results may be obtained with very little current. I havefound that by the arrangement herein shown I am able to produce resultswhich I have been unable to produce with any of the telephones now onthe market. Since the primary circuit is the main line, it is onlynecessary to have a source of electric supply or battery at one end ofthe line, and hence I am able to do away with a large number of sourcesof electric supply now used in the commercial operation of telephones.

I have described a simple construction embodying my invention for thepurpose of making it clear; but it is of course evident that myinvention is applicable to various constructions and arrangements, and Itherefore do not limit myself in any manner by the drawings shown.

The induction-coil, wherein the primary and secondary coils are woundupon a core of magnetic material mounted between the opposed pole-piecesof a permanent magnet, may be of any desired construction, and I haveshown a simple form for purposes of illustration. In this form the coreG and the primaryand secondary coils are mounted between the pole-piecesI-I of a permanent magnet. Attached to the ends of the core G are thecaps or plates G4, provided with the projecting parts G5, upon which thecore is mounted when the coils are adapted to be rotated to operate thesignaling device. It is of course evident that this rot-ation is notnecessary and is not used when the talkingcircuit is completed. Theseprojections G5, which constitute the shaft, are mounted in suitablebearings, which in this instance are obtained by means of the caps G,attached to the magnet.

I claim-- l. A telephone system, lcomprising at least two instrumentslocated at diiferent points, each comprising a receiver andatransmitter,means for connecting the two instruments together by an electriccircuit, an inductioncoil associated with each instrument, saidinduction-coil comprising a permanent magnet having opposed pole-pieces,with two separate coils wound upon a core of magnetic material mountedbetween said opposed polepieces, so as to form part of the magneticcircuit of the permanent magnet, one of said coils being the primarycoil and theother the secondary coil, the primary coil of cach inductioncoil being connected in the main circuit between the twoinstruments when the talking-circuit is completed.

2. A telephone system, comprising at least `two instruments located atdierent points, l each comprisinga receiver anda transmitter,

means for connecting the two instrumentstogether by an electric circuit,an induction coil associated with each instrument, said inpieces, so asto form part of the magnetic circuit of the permanent magnet, one ofsaid coilsbeing the primary coil and the other the secondary coil, theprimary coil of each induction-coil being connected in the main circuitbetween the two instruments when the talking-circuit is completed, thesecondary coil of each induction-coil connected in a local secondarycircuit with its associated receiver.

3. A telephone system, comprising at least two instruments located atdifferent points, each comprising a receiver, a transmitter, aninduction-coil and a signaling device, a main line connecting saidinstruments normally arranged so that the signaling devices and thesecondary coils of said induction-coils are in circuit, a switchingdevice associated with each instrument and adapted to vary the circuitsso as to connect the secondary coil of each instrument in a localcircuit with its associated receiver and to connect the two primarycoils and transmitters in the main line so as to form thetalking-circuit.

IOO

IOS

IIO

4. A telephone system, comprising atleast two instruments located atdifferent points, each instrument comprising av receiver, a transmitter,a signaling device and `an induction-coil, a main-line circuit betweenthe two instruments normally connected in circuit through the signalingdevices, a source of electric supply in the transmitter-circuit, a localsecondary circuit connected with the secondary coil of each instru mentnormally open, a switching device associated with each instrument andadapted when operated to vdisconnect the signaling device from the maincircuit and connect the transmitters and the primary coil of thetransformers in said main circuit and close the local secondary circuit.

5. A telephone system, comprising at least two instruments located atdifferent points, each instrument comprising a receiver, a transmitter,a signaling device and an induction-coil, a main-line circuit betweenthe two instruments normally connected in circuit through the signalingdevices, a source of electric supply in the transmitter-circuit, a localsecondary circuit connected with the secondary coil of each instrumentnormally open, a movable arm upon which each receiver is supported,aseries of contacts associated with each arm, said arms adapted to movewhen the receivers are taken therefrom, so as to disconnect thesignaling devices from the main circuit, close the local'secondarycircuit and connect the transmittersand the primary coils of theinduction-coils in said main circuit, substantially as described.

DAVID H. WILSON.

